// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "ui/events/devices/device_util_linux.h"

#include <string>

#include "base/files/file_enumerator.h"
#include "base/files/file_path.h"
#include "base/files/file_util.h"
#include "base/message_loop/message_loop.h"
#include "base/strings/string_util.h"

namespace ui {

base::FilePath GetInputPathInSys(const base::FilePath& path)
{
    return base::MakeAbsoluteFilePath(
        base::FilePath("/sys/class/input").Append(path.BaseName()));
}

InputDeviceType GetInputDeviceTypeFromPath(const base::FilePath& path)
{
    DCHECK(!base::MessageLoopForUI::IsCurrent());
    std::string event_node = path.BaseName().value();
    if (event_node.empty() || !base::StartsWith(event_node, "event", base::CompareCase::INSENSITIVE_ASCII))
        return InputDeviceType::INPUT_DEVICE_UNKNOWN;

    base::FilePath sysfs_path = GetInputPathInSys(path);

    // Device does not exist.
    if (sysfs_path.empty())
        return InputDeviceType::INPUT_DEVICE_UNKNOWN;

    // Check ancestor devices for a known bus attachment.
    for (base::FilePath path = sysfs_path; path != base::FilePath("/");
         path = path.DirName()) {
        // Bluetooth LE devices are virtual "uhid" devices.
        if (path == base::FilePath(FILE_PATH_LITERAL("/sys/devices/virtual/misc/uhid")))
            return InputDeviceType::INPUT_DEVICE_EXTERNAL;

        std::string subsystem_path = base::MakeAbsoluteFilePath(path.Append(FILE_PATH_LITERAL("subsystem")))
                                         .value();
        if (subsystem_path.empty())
            continue;

        // Internal bus attachments.
        if (subsystem_path == "/sys/bus/pci")
            return InputDeviceType::INPUT_DEVICE_INTERNAL;
        if (subsystem_path == "/sys/bus/i2c")
            return InputDeviceType::INPUT_DEVICE_INTERNAL;
        if (subsystem_path == "/sys/bus/acpi")
            return InputDeviceType::INPUT_DEVICE_INTERNAL;
        if (subsystem_path == "/sys/bus/serio")
            return InputDeviceType::INPUT_DEVICE_INTERNAL;
        if (subsystem_path == "/sys/bus/platform")
            return InputDeviceType::INPUT_DEVICE_INTERNAL;

        // External bus attachments.
        if (subsystem_path == "/sys/bus/usb")
            return InputDeviceType::INPUT_DEVICE_EXTERNAL;
        if (subsystem_path == "/sys/class/bluetooth")
            return InputDeviceType::INPUT_DEVICE_EXTERNAL;
    }

    return InputDeviceType::INPUT_DEVICE_UNKNOWN;
}

} // namespace
